CN108262002A - A kind of preparation method and application for the Fe-Ti binary oxide adsorbents for removing antimony - Google Patents

Abstract

The invention discloses a preparation method and application of an Fe-Ti binary oxide adsorbent for removing antimony, belonging to the field of treatment of heavy metal polluted water bodies. The adsorbent of the present invention uses iron salt and titanium salt as raw materials, adjusts pH, co-precipitates, ultrasonically disperses, ages, centrifuges, washes, dries, grinds, and sieves to obtain the Fe Ti binary oxide adsorbent. The adsorbent combines the advantages of iron oxide and titanium oxide, has many rough microscopic adsorption pores and a large specific surface area, the surface contains abundant hydroxyl groups, fast adsorption speed, high adsorption capacity, and can selectively and synergistically adsorb wastewater Antimony in. The adsorbent of the invention can be applied to deep purification and safety control of antimony in waste water.

Description

A kind of preparation method and application of Fe-Ti binary oxide adsorbent for removing antimony

technical field

The invention belongs to the field of treatment of heavy metal polluted water bodies, and is especially suitable for deep purification and safety control of antimony in industrial waste water, domestic sewage, ground water and sudden polluted waste water. Specifically relates to a preparation method and application of an Fe-Ti binary oxide adsorbent for removing antimony.

Background technique

Antimony, as an important non-ferrous metal, is regarded as one of the global strategic resources and is used in many industrial fields. The reserves and output of antimony in my country rank first in the world. In recent years, natural movement and human activities have exacerbated antimony pollution. Antimony-containing wastes have been released into natural water bodies through rock weathering, atmospheric deposition, rainwater erosion, and human discharge. Antimony pollution has become very common. Antimony is a toxic and harmful element. Antimony is listed as hazardous waste in the Basel Convention. It has strong biological toxicity (carcinogenic, teratogenic, mutagenic) to organisms. After absorption, it can interact with the sulfhydryl group of certain enzymes in the body Combined, destroy tissue metabolism, damage the heart, liver, kidney and nervous system. Therefore, the country has formulated strict antimony discharge standards: "Tin, antimony, mercury industrial pollutant discharge standards" (GB30770-2014) stipulates that the total antimony discharge standard of existing enterprises that produce antimony mineral products and antimony metal products is 1.0mg/ L, "Environmental Quality Standards for Surface Water" (GB 3838-2002) The standard limit value of antimony for specific items of centralized drinking water surface water sources is 0.005mg/L, and the antimony content in "Sanitary Standards for Drinking Water" (GB5749-2006) The upper limit is 5μg/L. Therefore, the treatment of antimony wastewater is urgent, and the efficient and economical treatment of antimony wastewater has great social, economic and environmental significance.

At present, antimony treatment processes usually use lime neutralization, electrochemical precipitation, enhanced coagulation precipitation, adsorption, ion exchange and membrane separation. Among them, the adsorption method is mostly used in the advanced treatment of wastewater due to its advantages of low cost, high removal efficiency, less sludge generation, simple operation and easy engineering implementation. The core of adsorption technology lies in the development of adsorbents, but most adsorbents have the disadvantages of obvious swelling, weak adsorption reaction activity, low adsorption capacity and adsorption selectivity, serious dissolution of harmful ions, and frequent regeneration. The special chemical properties, which have different morphological changes under different environmental (Eh-pH) conditions, bring difficulties to the removal of antimony. In recent years, iron-based adsorption materials such as zero-valent iron and iron oxides have been widely used in the adsorption and removal of heavy metals, but single iron-based adsorption materials have weak reactivity, adsorption capacity and adsorption selectivity. low-level disadvantages. Studies have shown that composite double oxides have a wider range of Eh-pH applications, stronger reactivity, higher adsorption capacity and adsorption efficiency than single oxides. At present, there is still a lack of efficient adsorbents for the deep adsorption treatment of antimony-contaminated wastewater at home and abroad. Therefore, it is of great significance to develop an adsorbent material with large adsorption capacity, which is economical and reliable.

Contents of the invention

The object of the present invention is to synthesize an economical and environment-friendly adsorption material with large specific surface area, large adsorption capacity, high adsorption efficiency, low operating cost, no secondary pollution, and no secondary pollution by coprecipitation of Fe ions and Ti ions under alkaline conditions.

The purpose of the present invention is achieved in the following manner:

A kind of preparation method of the Fe-Ti binary oxide adsorbent that removes antimony provided by the invention, concrete steps are as follows:

A, iron salt and titanium salt are respectively dissolved in anaerobic deionized water in a molar ratio of 0.2-5:1;

B. Vigorously stir the mixed solution in step A with a magnetic stirrer at a rotating speed of 1000rpm. After it is fully mixed, add 1M NaOH aqueous solution to keep the pH within the range of 5.0-7.0;

C. Ultrasonic disperse the mixed solution obtained in step B for 10-50 minutes to obtain a suspension, and continue to stir the suspension at a speed of 200 rpm for 0.5-1.0 h, then age at room temperature for 2-6 h, and filter to obtain a brown precipitate;

D, the brown precipitate obtained in step C is washed 5 times with deionized water, and the volume ratio of the volume of deionized water used for each washing to the volume of the reaction system is 2:1, until the pH of the clear water after washing is 7.0, and the suspension is obtained. solid;

E. Centrifuge the suspended solid obtained after step D to discard the supernatant, then vacuum-dry it at 110-150°C to constant weight, then grind the obtained dry solid into powder and pass it through a 200-mesh sieve to obtain the Fe-Ti binary oxide adsorbent for antimony removal;

Further, the iron salt belongs to one or more of ferric nitrate, ferric chloride, and ferric sulfate, and the titanium salt belongs to one or more of titanium nitrate, titanium chloride, and titanium sulfate;

Further, the molar ratio of the iron salt and the titanium salt is 2:1;

Further, the pH in step B is maintained at 6.00±0.02.

Another object of the present invention is to also provide an application of Fe-Ti binary oxide adsorbent in deep purification and safety control of antimony in industrial wastewater, domestic sewage, groundwater and sudden pollution wastewater.

The preparation method of Fe-Ti binary oxide adsorbent of the present invention has the following advantages:

(1) The preparation method of the present invention is simple, does not need high temperature and high pressure, the conditions are easy to control, the risk is low, and the environment is friendly; the cost of raw materials is low, and the energy consumption is low;

(2) Fe-Ti binary oxide sorbent prepared by the present invention has the advantages of iron oxide and copper oxide concurrently, and the surface has abundant hydroxyl groups, which makes up for the deficiency when the oxide alone is used simultaneously, and improves antimony Synergistic adsorption and removal capacity;

(3) The Fe-Ti binary oxide adsorbent prepared by the present invention has superior adsorption properties for antimonate ions in water. It is suitable for the purification and removal of antimony in ordinary drinking water, ground water and sudden pollution of drinking water;

(4) The present invention utilizes the synergistic system of synthetic Fe-Ti binary oxide adsorbent to remove antimony with high efficiency, very stable effect, low cost, little environmental interference, easy control and automatic operation.

Description of drawings

Fig. 1 SEM image of Fe-Ti binary oxide.

Fig. 2 XRD ray diffraction pattern of Fe-Ti binary oxide.

Figure 3 Adsorption and removal of antimony by Fe-Ti binary oxides under different pH conditions.

Figure 4 The adsorption kinetics curve of Fe-Ti binary oxides on antimony.

Fig. 5 Infrared diffraction patterns of Fe-Ti adsorbent before and after adsorption of antimony (V).

Figure 6 Schematic diagram of the filter column experimental setup for antimony removal.

In Figure 6: 1. Antimony-containing wastewater, 2. Stirring device, 3. Water inlet pipe, 4. Peristaltic pump, 5. Filter column, 6. Adsorption material, 7. Quartz sand, 8. Absorbent cotton, 9. Outlet pipe, 10 , Supporting device.

Detailed ways

The present invention will be further described below in conjunction with specific embodiments.

Embodiment 1: A kind of preparation method (as shown in Figure 1) of Fe-Ti binary oxide adsorbent for antimony of the present invention

Under magnetic stirring (100rpm), slowly inject 0.25mol titanium tetrachloride (TiCl ₄ ) into 1L of 0.5M ferric chloride (dissolved in 0.1M HCl) solution; at the same time, slowly add 1M NaOH solution dropwise until the pH value Keep it at 6.00±0.02, ultrasonically disperse the mixture for 30 minutes to obtain a suspension, and keep stirring the suspension at a speed of 200 rpm for 0.8 hours; then age the gelatinous yellow-brown precipitate in the mother liquor for 4 days; Make the surface of the adsorption material generate an activated layer with strong adsorption capacity, precipitate and separate the solid and liquid, wash the brown-yellow precipitate with deionized water 5 times, and the volume ratio of the volume of each washing water to the reaction system is 2:1, until the washing The pH of the clear water is 7.0, and the suspended solid is centrifuged and freeze-dried, and then dried to constant weight at 130°C; ground into powder and passed through a 200-mesh sieve to obtain Fe-Ti binary oxide adsorbent.

Embodiment 2: A kind of preparation method of Fe-Ti binary oxide adsorbent for antimony of the present invention (as shown in Figure 1)

In the state of magnetic stirring (100rpm), slowly inject 1mol of titanium sulfate into 1L of 0.2M ferric sulfate (dissolved in 0.1M HCl) solution; at the same time, slowly add 1M NaOH solution dropwise until the pH value remains at 5.0, and ultrasonically disperse the mixture After 10 minutes, the suspension was obtained, and the suspension was stirred at a speed of 200 rpm for 0.5 hours; then the gelatinous yellow-brown precipitate was aged in the mother liquor for 2 days; the surface of the adsorption material was activated to generate a strong adsorption capacity. layer, precipitation and solid-liquid separation, the brown-yellow precipitate was washed 5 times with deionized water, the volume ratio of each washing water to the reaction system was 2:1, until the pH of the washed water was 7.0, the suspended solid was centrifuged and frozen After drying, it is dried at 110°C to constant weight; it is ground into powder and passed through a 200-mesh sieve to obtain Fe-Ti binary oxide adsorbent.

Embodiment 3: A kind of preparation method of Fe-Ti binary oxide adsorbent for antimony of the present invention (as shown in Figure 1)

Under magnetic stirring (100rpm), slowly inject 1mol of titanium nitrate into 1L of 5M ferric nitrate (dissolved in 0.1M HCl) solution; at the same time, slowly add 1M NaOH solution dropwise until the pH value remains at 7.0, and ultrasonically disperse the mixture for 50min After obtaining the suspension, the suspension is 200rpm according to the rotating speed, and continues to stir for 1h; then the gelatinous yellow-brown precipitate is aged in the mother liquor for 6 days; the surface of the adsorption material is made to generate an active layer with strong adsorption capacity. Precipitation and solid-liquid separation, wash the brown-yellow precipitate with deionized water 5 times, the volume ratio of each washing water to the reaction system is 2:1, until the pH of the washed water is 7.0, the suspended solid is centrifuged and freeze-dried , dried at 150°C to constant weight; ground into powder and passed through a 200-mesh sieve to obtain Fe-Ti binary oxide adsorbent.

Experimental Example 1: Electron microscope scanning and XRD diffraction characterization of Fe-Ti binary oxide adsorbent synthetic material for antimony removal (as shown in Figure 1-2)

Scanning electron microscopy (SEM) shows that the prepared Fe-Ti binary oxide adsorbent has micron-scale aggregated tiny particles, a large number of overlapping and aggregated nanoparticles, and protrusions on the surface similar to coral reefs clustered into clusters, and the protrusion surface has more rough microscopic Adsorption pore structure and large specific surface area (232.339m ² /g), the minimum particle size is 0.486μm, and the average particle size is 6.88μm. The results of XRD diffraction pattern show that its surface is an amorphous structure. The surface of the material is rich in high-density hydrophilic hydroxyl groups, which are adsorbed on the solid surface. It has strong adsorption capacity for antimony in wastewater, high adsorption capacity, fast adsorption speed, and can be reused. , has strong practical application value.

Experimental Example 2: The experiment of adsorption and removal of antimony (V) by Fe-Ti binary oxides under different pH conditions (as shown in Figure 3)

Add 30mL of Sb(V) solution with an initial concentration of 10mg/L into a 40mL polyethylene plastic centrifuge tube, then add 0.015g of adsorbent, and control the pH of the solution to be 2, 3, 4, 5, 6, 7, 8, 9 , 10, the temperature is controlled at 25°C, the rotation speed is 120rpm, and the temperature is oscillated for 24h, then a small amount of sample is taken, passed through a 0.45μm nitrocellulose filter membrane, diluted several times, and measured by LC-AFS97800 atomic fluorescence spectrometer in the liquid phase before and after adsorption. Concentration of Sb(V). It is concluded that the removal rate of antimony by Fe-Ti binary oxides is significantly affected by the pH value, and the removal rate under acidic conditions is significantly higher than that under alkaline conditions. The optimum pH is 6.00±0.02. The rate basically reached 99.31%.

Experimental example 3: The adsorption kinetic experiment of Fe-Ti binary oxide on antimony (as shown in Figure 4)

Add 0.02g of adsorbent to a 300mL polyethylene plastic centrifuge tube, add 200mL of Sb(V) solution with an initial concentration of 10mg/L, adjust the optimum pH value to 5.00±0.02, and put it into a full-temperature shaking incubator for adsorption experiments. at 25°C, the rotation speed is adjusted to 120rpm, the shaking time is 10min, 20min, 30min, 1h, 1.5h, 2h, 3h, 4h, 5h, 7h, 9h, 11h, 13h, 24h, 36h, 48h, 60h, 72h, and then Take about 0.5mL sample, pass through 0.45μm nitrocellulose filter, dilute several times, and measure the concentration of Sb(V) with LC-AFS97800 atomic fluorescence spectrometer. The adsorption amount is calculated from the difference between the initial concentration C ₀ and the concentration difference C _e at different times: with the continuous increase of time, the adsorption amount of Fe-Ti binary oxide to antimony (V) is also increasing, and at 60h At that time, its maximum adsorption capacity was 69.96mg/g.

Experimental example 4: Infrared diffraction patterns of Fe-Ti binary oxide before and after adsorption of antimony (as shown in Figure 5)

It can be seen from the figure that a strong peak around 1350cm ^-1 may be produced by the nitrate or carbonate adsorbed on the surface of the adsorbent. The nitrate and carbonate may be adsorbed on the surface of the adsorbent during the preparation process. During the adsorption process, it is replaced. For Fe-Ti adsorbent: the weaker peak around 1650cm ^-1 is produced by the bending vibration of the OH group on the surface of the adsorbent; the broad peak around 3350cm ^-1 is produced by the stretching vibration of the OH group on the surface of the adsorbent ; the size of these two peaks changed before and after adsorption, showing that the antimony adsorption occurred on the OH group.

Application example: Fe-Ti binary oxide adsorbent filter column for antimony (V) removal application example (as shown in Figure 6)

Use potassium pyroantimonate (K ₂ H ₂ Sb ₂ O ₇ 4H ₂ O) to prepare 500 μg/L wastewater in a 1L Erlenmeyer flask, adjust the pH to 6.00±0.02 with 0.1mol/L HCl/NaOH solution, and stir After the filter is stirred evenly, it is pumped into the filter column with a peristaltic pump, and the Fe-Ti binary oxide adsorbent is filled in the column (the bottom of the column is filled with absorbent cotton). HRT is 10min, samples are taken from the outlet at regular intervals, and the concentration of antimony (V) is measured. The experimental results are shown in Table 1. From the experimental results, it can be concluded that the Fe-Ti binary oxide adsorbent has a positive effect on the concentration of antimony (V) After the wastewater is treated, its effluent meets the drainage standard (Sb<5μg/L) of the Hygienic Standard for Drinking Water (GB5749-2006).

Table 1: Experimental results of multiple batches of Fe-Ti binary oxides for the removal of antimony (V)-containing wastewater

frequency Antimony (V) influent concentration (μg/L) Antimony (V) effluent concentration (μg/L) Antimony (V) removal rate (%) 1 500 2.97 99.40 2 500 3.35 99.33 3 500 4.03 99.19 4 500 4.01 99.20 5 500 4.21 99.16 average value 500 3.74 99.31

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the protection of the present invention. within range.

Claims (5)

1. a kind of preparation method for the Fe-Ti binary oxide adsorbents for removing antimony, which is characterized in that this method includes following step Suddenly：

A, by molysite and titanium salt, example is dissolved in for 0.2-5: 1 in anaerobic deionized water respectively in molar ratio；

B, it is mixed liquor that 1000rpm is vigorously stirred in step A by rotating speed with magnetic stirring apparatus, after it is sufficiently mixed, adds PH is maintained in the range of 5.0-7.0 by the NaOH aqueous solutions for entering 1M；

C, suspension will be obtained after mixed liquor ultrasonic disperse 10-50min that step B is obtained, is by rotating speed by the suspension 200rpm continues to stir 0.5-1.0h, is then aged 2-6h at room temperature, brown precipitate is obtained by filtration；

D, the brown precipitate obtained by step C is cleaned 5 times with deionized water, the volume of the deionized water of each washing with it is anti- The volume ratio for answering system is 2: 1, until the pH for washing clear water is 7.0, obtains suspended solid；

E, the suspended solid obtained after step D is centrifuged and is dried under vacuum to constant weight at 110-150 DEG C after discarding supernatant liquid, so Obtained dried solidss are pulverized into last 200 mesh of mistake sieve to get to the Fe-Ti binary oxides of the removal antimony afterwards Adsorbent.

2. the Fe-Ti binary oxide adsorbents of removal antimony according to claim 1, which is characterized in that the molysite Belong to one or more of ferric nitrate, iron chloride, ferric sulfate, the titanium salt belongs in Titanium Nitrate, titanium chloride, titanium sulfate It is one or more of.

3. the preparation method of the Fe-Ti binary oxide adsorbents of removal antimony according to claim 1, which is characterized in that The molysite and titanium salt molar ratio are 2: 1.

4. the preparation method of the Fe-Ti binary oxide adsorbents of removal antimony according to claim 1, which is characterized in that PH described in step B is maintained at 6.00 ± 0.02.

5. the Fe-Ti binary oxide adsorbents that the preparation method according to any one of claim 1-4 obtains are in industry Waste water, sanitary sewage, underground water and burst Pollution Antimony in Waste Water deep purifying and security control in application.